Repeaters for use in cellular and other communication applications, e.g. in elevator piers or in large facilities, are well known. For example, a Wifi or other router may have a range of 30-50 m surrounding it; a repeater which receives an RF signal and retransmits it, may be positioned each 20-30 meters beyond this so as to effectively extend the coverage range of the router.
Layer 1, 2 and 3 relays are known.
Many different communication protocols such as LTE, 3G UMTS, WiMAX, WiFi are known.
State of the art repeaters and associated systems are described in U.S. Pat. No. 7,003,291 to ZHNAG, U.S. Pat. No. 4,475,243 and U.S. Pat. No. 4,941,200.
The disclosures of all publications and patent documents mentioned in the specification, and of the publications and patent documents cited therein directly or indirectly, and of specifications of mentioned protocols are hereby incorporated by reference.